The proposed fix is, ironically, another ditch: the Third Delta Conveyance Channel, a 30-to-40-foot-deep, 350-foot-wide, 100-mile-long channel off the Mississippi that will transport 20,000 cubic feet of water per second into the Gulf. Over 20 to 60 years, the channel is supposed to erode until it's 1,000 feet wide, 50 to 60 feet deep, and flowing at 200,000 cubic feet per second, delivering enough sediment to rebuild the marshes around Louisiana's barrier islands. "Most diversions drop sediment along their route rather than carry it to where it needs to go," says Bob Roberts, Louisiana State Department of Natural Resources manager for the project. "That's why we need such a big, high-velocity channel. Will this thing erode like we want it to, and then can we control it? We still don't know."